Update Tinyusb Build System Integration (#1)

* Update tinyusb build system integration

- Swap out Makefile for latest project "driver" Makefile.  The only
  difference here is that TARGET is floating.
- Simplify tinyusb.mk
- Add build-specific configuration to project.mk, and simplify
  IPATH/VPATH requirements
- Add clean.tinyusb
- Build library inside the tinyusb library by default
- Add default configuration directory

* Use override on PROJECT

Libraries/libs.mk

@@ -191,8 +191,8 @@ endif
 LIB_TINYUSB ?= 0
 ifeq ($(LIB_TINYUSB), 1)
 TINYUSB_DIR ?= $(LIBS_DIR)/tinyusb
-TINYUSB_CONFIG_DIR ?= .
 include $(TINYUSB_DIR)/tinyusb.mk
+libclean: clean.tinyusb
 endif
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